This section is intended to provide a background or context to the invention disclosed below. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived, implemented or described. Therefore, unless otherwise explicitly indicated herein, what is described in this section is not prior art to the description in this application and is not admitted to be prior art by inclusion in this section. Abbreviations that may be found in the specification and/or the drawing figures are defined below, after the main part of the detailed description section.
A work item called “UE Positioning Accuracy Enhancements for LTE” has been approved for 3GPP Rel-15. See Nokia, Nokia Shanghai Bell, “WID Update: UE Positioning Accuracy Enhancements for LTE”, RP-172313, 3GPP TSG RAN Meeting #78, Lisbon, Portugal, 18-21 Dec. 2017. One of the main objectives of the work item is broadcasting of positioning assistance data using the LTE system information broadcast mechanism. This requires new LPPa (LTE Positioning Protocol “a”) procedure(s) to convey the assistance data from an E-SMLC to an eNB, and to trigger the broadcasting of the assistance data over the air interface in System Information Blocks (SIBs).
Multiple SIBs are expected to be defined for the assistance data, as follows.
1) Different SIBs for different positioning methods (e.g., RTK, GNSS, OTDOA).
2) For a given positioning method, different SIBs for different “parts” of the assistance data. For example, some data may need to be refreshed more frequently, or needed only for extremely accurate positioning, and the like.
Some SIBs are expected to be very large due to the size of the assistance data defined for the SIB, thus segmentation will likely be needed due to message size limitations in the radio protocol (RRC). That is, while SIB messages themselves might be not be able to be segmented, the content broadcast in SIB messages can be segmented (i.e., application-level segmentation and not RRC layer segmentation).
There are multiple different options, described below, for handling and sending these SIBs, but these options could be improved.